FIRE FI Number Math: How to Calculate What You Actually Need 25x annual expenses is the headline rule. For anyone retiring before 55, the real number is 30-33x. The difference is healthcare and sequence risk.
4% rule The 4% Rule: Is It Still Safe After 2022-2024 Bill Bengen's original 1994 study used historical data through 1992. After three down years, does $40,000 on $1 million still work? The data says yes, with one adjustment.